A lot of swimming space is necessary. Decorate with rock work, bogwood/driftwood and sturdy plants such as Amazon Swords and Giant Vallisneria. An agitated Silver Arowana may uproot plants with poor root systems.
6 or more juveniles can be kept together, but 10 or more is better. The same with adults, but this is a gamble as some adults do not tolerate others of their own kind well. Besides keeping them in schools they should be kept with peaceful to moderately aggressive fish that cannot be eaten and that will not harass the Arowana.
It is critical that the aquarium has a tight fitting and secured lid that is extremely strong. Arownas are avid jumpers and can easily knock a heavy glass lid onto the floor! Many an Arowana has been lost this way. They do not tolerate poor water quality, so excellent filtration along with frequent partial water changes of 25% or more is required to keep nitrates low.
Their tank should be placed in low traffic areas to keep the Arowana from getting frightened by sudden movements. They can be shy and easily spooked. For example, when turning on the lights, it is wise to turn on the room lights first. Then after a few minutes, turn on the tank lights. Otherwise, your Silver Arowana might get spooked and injure itself.
Silver Arowana are among the cheapest Arowana available, and the least restricted to import/export. They come small but look out, they grow rapidly. It is wise to get them after their eggsack has been completely absorbed and are at least 4 – 8 inches/ 10 – 20cm in length when they are hardier and easier to handle. This will give you a better chance of success keeping them.